From c214f124161d446b340597e7c968e0a2dc149142 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Tue, 9 Nov 2021 19:57:10 +0000 Subject: arch_topology: Introduce thermal pressure update function The thermal pressure is a mechanism which is used for providing information about reduced CPU performance to the scheduler. Usually code has to convert the value from frequency units into capacity units, which are understandable by the scheduler. Create a common conversion code which can be just used via a handy API. Internally, the topology_update_thermal_pressure() operates on frequency in MHz and max CPU frequency is taken from 'freq_factor' (per-cpu). Signed-off-by: Lukasz Luba Reviewed-by: Thara Gopinath Signed-off-by: Viresh Kumar --- drivers/base/arch_topology.c | 43 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 42 insertions(+), 1 deletion(-) (limited to 'drivers/base') diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index ff16a36a908b..a3ae0b4eea09 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -22,6 +22,7 @@ static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data); static struct cpumask scale_freq_counters_mask; static bool scale_freq_invariant; +static DEFINE_PER_CPU(u32, freq_factor) = 1; static bool supports_scale_freq_counters(const struct cpumask *cpus) { @@ -165,6 +166,47 @@ void topology_set_thermal_pressure(const struct cpumask *cpus, } EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); +/** + * topology_update_thermal_pressure() - Update thermal pressure for CPUs + * @cpus : The related CPUs for which capacity has been reduced + * @capped_freq : The maximum allowed frequency that CPUs can run at + * + * Update the value of thermal pressure for all @cpus in the mask. The + * cpumask should include all (online+offline) affected CPUs, to avoid + * operating on stale data when hot-plug is used for some CPUs. The + * @capped_freq reflects the currently allowed max CPUs frequency due to + * thermal capping. It might be also a boost frequency value, which is bigger + * than the internal 'freq_factor' max frequency. In such case the pressure + * value should simply be removed, since this is an indication that there is + * no thermal throttling. The @capped_freq must be provided in kHz. + */ +void topology_update_thermal_pressure(const struct cpumask *cpus, + unsigned long capped_freq) +{ + unsigned long max_capacity, capacity; + u32 max_freq; + int cpu; + + cpu = cpumask_first(cpus); + max_capacity = arch_scale_cpu_capacity(cpu); + max_freq = per_cpu(freq_factor, cpu); + + /* Convert to MHz scale which is used in 'freq_factor' */ + capped_freq /= 1000; + + /* + * Handle properly the boost frequencies, which should simply clean + * the thermal pressure value. + */ + if (max_freq <= capped_freq) + capacity = max_capacity; + else + capacity = mult_frac(max_capacity, capped_freq, max_freq); + + arch_set_thermal_pressure(cpus, max_capacity - capacity); +} +EXPORT_SYMBOL_GPL(topology_update_thermal_pressure); + static ssize_t cpu_capacity_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -217,7 +259,6 @@ static void update_topology_flags_workfn(struct work_struct *work) update_topology = 0; } -static DEFINE_PER_CPU(u32, freq_factor) = 1; static u32 *raw_capacity; static int free_raw_capacity(void) -- cgit From 7e97b3dc2556743dd02612c92a8de7026e8d7dc9 Mon Sep 17 00:00:00 2001 From: Lukasz Luba Date: Tue, 9 Nov 2021 19:57:14 +0000 Subject: arch_topology: Remove unused topology_set_thermal_pressure() and related There is no need of this function (and related) since code has been converted to use the new arch_update_thermal_pressure() API. The old code can be removed. Signed-off-by: Lukasz Luba Signed-off-by: Viresh Kumar --- drivers/base/arch_topology.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index a3ae0b4eea09..976154140f0b 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -156,16 +156,6 @@ void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity) DEFINE_PER_CPU(unsigned long, thermal_pressure); -void topology_set_thermal_pressure(const struct cpumask *cpus, - unsigned long th_pressure) -{ - int cpu; - - for_each_cpu(cpu, cpus) - WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure); -} -EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); - /** * topology_update_thermal_pressure() - Update thermal pressure for CPUs * @cpus : The related CPUs for which capacity has been reduced @@ -183,7 +173,7 @@ EXPORT_SYMBOL_GPL(topology_set_thermal_pressure); void topology_update_thermal_pressure(const struct cpumask *cpus, unsigned long capped_freq) { - unsigned long max_capacity, capacity; + unsigned long max_capacity, capacity, th_pressure; u32 max_freq; int cpu; @@ -203,7 +193,10 @@ void topology_update_thermal_pressure(const struct cpumask *cpus, else capacity = mult_frac(max_capacity, capped_freq, max_freq); - arch_set_thermal_pressure(cpus, max_capacity - capacity); + th_pressure = max_capacity - capacity; + + for_each_cpu(cpu, cpus) + WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure); } EXPORT_SYMBOL_GPL(topology_update_thermal_pressure); -- cgit